Browsing by Author "Yao, Lina"

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    Intracellular Na+ overload causes oxidation of CaMKII and leads to Ca2+ mishandling in isolated ventricular myocytes
    (Elsevier, 2014-11) Viatchenko-Karpinski, Serge; Kornyeyev, Dmytro; El-Bizri, Nesrine; Budas, Grant; Fan, Peidong; Jiang, Zhan; Yang, Jin; Anderson, Mark E.; Shryock, John C.; Chang, Ching-Pin; Belardinelli, Luiz; Yao, Lina; Department of Medicine, IU School of Medicine
    An increase of late Na(+) current (INaL) in cardiac myocytes can raise the cytosolic Na(+) concentration and is associated with activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and alterations of mitochondrial metabolism and Ca(2+) handling by sarcoplasmic reticulum (SR). We tested the hypothesis that augmentation of INaL can increase mitochondrial reactive oxygen species (ROS) production and oxidation of CaMKII, resulting in spontaneous SR Ca(2+) release and increased diastolic Ca(2+) in myocytes. Increases of INaL and/or of the cytosolic Na(+) concentration led to mitochondrial ROS production and oxidation of CaMKII to cause dysregulation of Ca(2+) handling in rabbit cardiac myocytes.
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    Targeting LOXL2 for cardiac interstitial fibrosis and heart failure treatment
    (SpringerNature, 2016-12-14) Yang, Jin; Savvatis, Konstantinos; Kang, Jong Seok; Fan, Peidong; Zhong, Hongyan; Schwartz, Karen; Barry, Vivian; Mikels-Vigdal, Amanda; Karpinski, Serge; Kornyeyev, Dmytro; Adamkewicz, Joanne; Feng, Xuhui; Zhou, Qiong; Shang, Ching; Kumar, Praveen; Phan, Dillon; Kasner, Mario; Lopez, Begona; Diez, Javier; Wright, Keith C.; Kovacs, Roxanne L.; Chen, Peng-Sheng; Quertermous, Thomas; Smith, Victoria; Yao, Lina; Tschope, Carsten; Chang, Ching-Pin; Department of Medicine, IU School of Medicine
    Interstitial fibrosis plays a key role in the development and progression of heart failure. Here, we show that an enzyme that crosslinks collagen-Lysyl oxidase-like 2 (Loxl2)-is essential for interstitial fibrosis and mechanical dysfunction of pathologically stressed hearts. In mice, cardiac stress activates fibroblasts to express and secrete Loxl2 into the interstitium, triggering fibrosis, systolic and diastolic dysfunction of stressed hearts. Antibody-mediated inhibition or genetic disruption of Loxl2 greatly reduces stress-induced cardiac fibrosis and chamber dilatation, improving systolic and diastolic functions. Loxl2 stimulates cardiac fibroblasts through PI3K/AKT to produce TGF-β2, promoting fibroblast-to-myofibroblast transformation; Loxl2 also acts downstream of TGF-β2 to stimulate myofibroblast migration. In diseased human hearts, LOXL2 is upregulated in cardiac interstitium; its levels correlate with collagen crosslinking and cardiac dysfunction. LOXL2 is also elevated in the serum of heart failure (HF) patients, correlating with other HF biomarkers, suggesting a conserved LOXL2-mediated mechanism of human HF.